Treatment of plastic material.



UNITED .sTATEs P TEN OFFICE.

RAYMOND IB. PRICE, on NEW YORK, Y., ASSIGNOR TO RUBBER REGENERATING COMPANY, A CORPORATION OF I DIANA.

TREATMENT OF PLASTIC MATERIAL.

No Drawing.

To all whom it may concern.

Be it known that LRAYMOND B. PRICE,

a citizen of the United States, residing in w the borough of Manhattan, city of New York, State of New York, have invented new and useful Improvements in the Treatment of Plastic Material, of which the following is a specification. 4

My invention relates toftheyulcanization of rubber, and has fOrits-objeCt to provide an improved process of vulcanizing the same whereby a better product will be produced.

In carrying out my process the stock to be treated is subjected to a minor heating action below the vulcanizing heat, and which may be applied to the material at or slightly above atmospheric pressure or under a vacuum, or under a combination of these conditlons, in any desired order of appl1cation. -Or I may, if desired, first apply the vacuum and then the minor heat, either while the vacuum is continued or afterit is broken. Having applied this heat sufficiently to warm "the stock throughout, Ithen introduce to the chamber containing the stock il/ VHPOI, such as superheated steam, for elfecting the vulcanizing operation,

which may be introduced at any desired temperature and at any desired pressure. It will be found that this preliminary warming of the material expands any gas or volatile matter therein, so that the application of a vacuum will more readily draw out the same. Said warming step also tends to flux the external surface of the material, and, further, and what is quite important, renders the material more receptive of the vulcanizing action of the steam by limiting its condensation.

It will be understood that when the vulcanization has been started by means of superheated steam, wet steam may be substituted without injuriously affecting the product, or wet steam or any other such medium may be used. '7

While I have described my process as pri marily intended for use in vulcanizing rubber, it will be understood that the same may Specification of Letters Patent, Patented NOV. 30, 1915. I

Application filed January 25, 1913. Serial NO. 744,254.

be applied to the treatment of other analogous substances, such as balata and the like.

Havingv thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. The process of vulcanizing rubber or the like which consists in preheating the material to be vulcanized by subjecting it to the action of heat below the vulcanizing temperature and to a reduced external pressure for a definite period of time, whereby entrapped fluids will be withdrawn therefrom, and thereafter subjecting the material to the action of a medium at a vulcanizing temperature.

2. The process of vulcanizing rubber or the like which consists in preheating the material to be vulcanized by subjecting it to the action of heat below the vulcanizing temperature and to a reduced external pressure for a definite period of time, whereby entrapped' fiuids will be expanded and withdrawn therefrom, and immediately thereafter subjecting the material while still material'to be vulcanized by subjecting it to the action of heat below the vulcanizing temperature for a definite period of time, then subjecting the material to reduced external pressure, whereby expanded entrapped fiuids will be withdrawn therefrom, and thereafter subjecting the material to the action of a dry vapor ata vulcanizing temperature.

5. The process of vulcanizing rubber or the like which consists in preheating the temperature, Withdrawing therefrom the Witnesses.

Q memee I material to be vulcanized by subjectihg it In testimony whereof, I have hereunto set to the action of-heat below the vulcanizing my hand inthe presence of two subscribing flu'i d' entrapped therein by subjecting the RAYMOND B. PRICE.

material to the action of a vacuum and. there- Witnesses after subjecting the material to the action 01 PERCY B. HILLS, a dry vapor at a vulcenizing temperature. A. L. MILLS. 

